Field
Systems and methods can provide alternatives to a global positioning system (GPS). For example, certain systems can operate on 1090 MHz and provide for methods of estimating location that can be used in place of GPS.
Description of the Related Art
The Global Positioning System, GPS, being used for the NextGen automatic dependent surveillance-broadcast, ADS-B, primary surveillance source may benefit from a backup. GPS can be easily jammed in a local area using methods that include deliberate jamming by the military and uncontrolled illegal jamming. GPS also has time periods of low integrity and accuracy due to real time changing satellite geometries, sometimes resulting in inadequate information for ADS-B applications.